by Elizabeth Weise, USA TODAY

by Elizabeth Weise, USA TODAY

Those willing to endure some cold and stay up past their bedtimes are about to be treated to the annual Geminid meteor shower.

This year's shower begins to peak just after midnight Thursday (the early-morning hours of Friday) and lasts through dawn. The 48-hours of prime viewing will continue through the predawn hours of Saturday. Falling stars should be visible beginning mid-to-late evening and ending at dawn both nights.

The shower, whose origins are mysterious, will be partly obscured by a waxing moon, but those who venture into the cold should be rewarded by seeing at least a few shooting stars, astronomers say.

The meteors will start out few and far between in early evening but will increase in number as evening deepens into late night. Worldwide, these meteors will fall most abundantly in the hours after midnight, with the largest concentration at 2 a.m. local time.

"Meteor showers have personalities," says Deborah Byrd, editor in chief of EarthSky.org, a science and astronomy site based in Austin, Texas. "The Geminids tend to be bright, and they tend to be white, so they can withstand a fair amount of moonlight."

The best way to see them "is to go to sleep for a few hours and then get up around 2 a.m. (local time)," Bryd says. The moon begins to slowly set about that time and will be fully down by 4 a.m. local time wherever the watcher is in North America.

"As the moon gets lower in the sky, it's going to be easier to see the meteors," she says. Standing in the shadow of a building to block the moon's light will also help. The light of the moon resets the eyes and makes it harder to see faint objects.

The moon is in its waxing phase and will be gibbous (more than half full) and up most of the night, so its light will compete with fainter meteors.

The Geminids get their name because they appear to emerge from the constellation Gemini. They're not actually coming from that group of stars, but from the Earth it looks that way.

They are one of the best meteor showers of the year, usually producing upwards of 50 falling stars an hour when there's no moon. Even with the moon's light interfering this year, a good number of meteors should be visible.

Meteor showers in general are caused when Earth passes through the dust trail left behind by a comet. "The dust bits burn up in the Earth's atmosphere as we plow through the cloud," says Benjamin Burress, an astronomer at the Chabot Space & Science Center in Oakland, Calif.

The Geminids "are specks of debris from 3200 Phaethon, which is not a comet, as you might expect, but an asteroid," says Rick Kline with the Planetary Imaging Facility at Cornell University in Ithaca, N.Y.

The asteroid is "a mysterious type of object sometimes called a "rock comet," says Burress. Astronomers don't quite understand how or why an asteroid is producing a comet-like stream of dust.

It was first noted as a minor meteor back in 1862, says William Cooke, an astronomer at the Meteoroid Environments Office at NASA's Marshall Space Flight Center in Huntsville, Ala.

At the time of the Civil War, the shower's peak rate was about 30 meteors an hour. "Since then, the Geminids have gradually strengthened to become the strongest annual shower, with peak rates of about 120 per hour. This is due to Jupiter's gravity nudging the stream closer to Earth," he says.

The shower actually lasts for longer than just two nights, says Ron Hipschman, a scientist at the Exploratorium, a science museum in San Francisco. "We actually run through the dust trail of 3200 Phaethon from Dec. 4 to Dec. 17." The portion of the trail the Earth will be going through is densest from Dec. 12-14, so that's when the most meteors will be visible.

Photographing meteors, especially if you're in a cold area, isn't for the faint of heart. Photographer Henry Shaw of Baltimore drives far from home until he gets somewhere with no light pollution from cities.

He sets up a very sensitive camera on a tripod and points it in the proper direction. "Then I just set that thing to rock and roll," he says. The camera shoots continuously and every time he sees a meteor flash across the sky he notes the exact time.

"That's so when I go back and edit the 12,000 or so frames I've taken over four hours, I can find the ones that actually have meteors in them," he says.

As for dealing with the cold, he's worked out a solution. "I have a lounger, a sleeping bag and an electric blanket. I plug the electric blanket into my car, stuff it inside the sleeping bag and turn myself into a mummy."